Automatic pressure sealing means



Ap1 il18,1933. H.-H-. um/ls 1,904,250

v AUTOMATIC ,PRESSURE SEALING MEANS Filed April 27, 1932' W2. BY

ATTORNEYS Patented 'Apr. 18, 1933 I ma n. runvrs, or roar PATENT OFFICE comm or mimics, a conrom'rrou or DELAWARE auronrrc rnnssuaa same name ama sled April 21,

This invention relates to apparatus for automatically producing a pressure-tight closure in a fluid contamerand more particularly refers to a gasket which is ballooned by the interior pressure in the-container or tank and associated structure and which thereby becomes capable of sealing pressures in the neighborhood of several thousand ounds per square inch without leaking.

laces such as soda fountains which dispense" charged liquids are usually furnished with a tank of liquid carbon dioxide which is usedat necessary intervalsto charge other liquids. Heretofore the common practice has been to remove an empty tank and substitute a filled one obtained from manufacturers.

The inconvenience of removing the charging apparatus and the labor connected with the 4 removal, and the delivery. and installation of a newly filled tank areall reflected in the cost of the commodity.

At the present time there is a method of producing such tanks containin liquid car.-

on dioxide on the premises at essened cost and without the drawbacks of the older system. This method involves the placing of a definite amount of solid carbon dioxide or dry ice in an empty tank and closing it with the usual plug. As. the internal pressure within the tank builds up the critical ressure atwhich the liquid can exist is reac ed and eventually the entire tank is converted to a tank of hquid carbon dioxide ready for use.

' As the pressures involved in this process amount in a fully charged tank to around a thousand pounds persquare inch, unless the seal. around the closing plug is absolutely pressure-tight a satisfactory result cannot be obtained. When a pressure-tight joint is so ht with the ordinary gasket heretofore u the closing members must be tightened to an extra-ordmary de and with an unusual amount of care. fare to close the tank by hand after inserting the dry ice without the use of wrenches or other tools necessary to tighten up the plug, there has arisen a real need for a gasket which prevents leakage around the closure member and utilizes the interior pressure in the tank for its eflective sealing.

the dispenser pre- 1932. Serial in. 607,687.

- m You, nssrenon 'roruan csnnoz'no whose effectiveness is attributable to the existence of unbalanced pressures distorting the gasket at the'necessary' points.

. Features of this invention are to be found in the ease of replenishment and the ease of replacement and of the lower cost of the roduct contained. Further features are ound in the fact that the closing of such a tank is an easy matter and that no precautions for sealing such high pressures have to be taken; furthermore, regardless of the shape of the vessel or the position ofthe o ning therein, the same results are obtainable by the use of this invention. Y

Applying the invention to the specific use previously. mentioned, dry carbon dioxide is placed inside of a tank and a loosely threaded screw plug is turned down into the mouth of thetank by hand. This plug is usually pro- "vided with a tap for a discharge valve.

Around the periphery of the plug on the under side thereof the surface is machined to make a machine fit but not a gas tight joint with a shoulder in the mouth of the tank. Leading from the flat surface on the under side of the plug is a small bevel followed by thehubto the side of the tank opening. When in place a U-shaped chamber is formed by the recess in the plug, the flange on the plate and a curved seat at the inner end of the shoulder at the tank mouth.

The dimensions of this chamber are exactly those of an elastic U-shaped gasket which, when the plug. is assembled and before it is tire half imbedded in the under side of the plug so that the joint between the plug and ,the tank is recisel in the center of the U of both chain r an gasket.

Closely fitting around the hub and inserted between the two sides of the U-shaped sket is a ring which is pierced to permit t e pressure in the interior of the tank to reach the interior of the balloonin gasket.

A smal arrowhead groove in the gasket chamber is formed by the bevels on the under side of the plug and on the edge of the shoulder in the mouth of the tank. As pressure builds up within the tank and balloons the distortionable gasket the unbalanced ressures between the outside and the insi e of the gasket tend to force the gasket against the curved. seat and to wedge a portion of the same into this groove and an effective seal for any pressure in the tank is made. In making the locking plate of a sizeto closely fit within the opening in the tank, the smallest part of the outside surface of the gasket is exposed to the tank pressure.

It is at this point that the gasket is most likely to be in equilibrium owing to a balance.

of pressures on both sides and seepage and consequent leakage is most likely to occur.

As the gasket is exactly contained and because there is no seepage around the rear of the gasket so as to build up pressure between the under side of the plug and the side of the gasket resting thereagainst, a true unbalanced pressure is produced in this ballooning gasket. Thus there is a sort of pressure ill) gradient increasing in unbalance from the lower side of the gasket all the way around to the upper side; Such seepage around the ends or sides of the gasket is reventedby means of the metal ring inserted therein and the locking plate which clamp these sides so that they are pressure tight and not liable to collapse orundue distortion.

Owing to this unbalance of pressure the gasket material will be thinner where the unalance is eatest producing a greater thickness of gas et at the points where would be the natural path of leakage. Thus the gasket without any balancing pressure on the outside of the upper portions is thinned by the distortion to a greater extent than the lower side where outside pressure is greater with the result that an elastic flow occurs making the thickness of the lower side greater than normal.

Although the described embodiment of the invention isdescribed largely in connection with one particular use, it is possible for a reverse application of the invention to be applied without falling outside of the scope of the invention. As for instance, if the passages in the hub leading to the interior of the were to lead to the exterior of the tanlr and the tank pumped out to provide a neoaaeo vacuum, the atmo here could then be relied apparent from the following description and drawing in which Fig. 1 is a side view of a liquid carbon dioxide tank with the discharge connections in ition;

ig. 2 is a view of the top of the tank in cross-section showin the closure means assembled which are t e object of this invention;

Fig. 3 is a perspective view showing the rinlg and gasket assembled together;

ig. 4 is a plan view of the locking plate alone; and

Fig. 5 is a greatly enlargedwiew of the end of the gasket chamber illustrating the arrowhead groove and the .wedging action of the gasket.

Referring to the drawlng, 10 indicates a circular steel tank for contaming a fluid un-. I

der pressure. A draining plug 11 with a discharge valve 12 and discharge line 13 are afiixed to the tank in the usual manner. A

wide mouth 14 at the top of the tank 10 is countersunk a short distance terminating in an interior flange 15. The distance between the sides of this flange measure the available openin 40 of the tank and should .be large enoug to satisfactorily insert dry ice or similar material. At the outermost portion of flan e 15 is a machined shoulder 16, the inner ezfge of which is beveled at 17 and from thence a curved seat 18 is made to the edge of opening 40.

Mouth 14 above'flange 15 is threaded at 19 to engage corresponding threads on a closing screw plug 20. This plug is made to screw loosely into tank 10 by hand. Around the base of threads 19 is a groove 21 to permit plu% 20 to be brought down hand-tight against ange 15. Plug 20 is usually tapped at 22 to accommodate a discharge valve 12.

The underside of plug 20 is machinedat 23 to form a surface which makes a nongas-tight joint with shoulder 16 when tank 10 is closed. Surface 23 has the dimensions of shoulder 16 and likewise the inner edge is beveled at 24. Bevels l7 and 24 form an arrowhead groove t1. Likewise again, plug 20 has anupper seat 25 making a semicircle 5 and ring 31 and that the lower side hub 26 has a circular flange 29 which fills the o ning 40 between hub 26 and flange 15. ese parts areaccurately fitted together and provide a circular U-shaped chamber between the under side of plug 20, locking plate 27 and seats 18'and 25.

A rubber U-sha d gasket 30 of uniform thickness havin t e same dimensions as this chamber or slig tly la r is adapted to fit horizontally therein wit the closed end outermost. A brass or steel ring 31 closely fitting around hub 26 is inserted between the sides of gasket 30 at the inner, 0 n end and serves to clamp the gasket an to prevent its collapse or improper distortion as indicated in Figs. 2 and 3. Ring 31 is formed with an annular channel 32 on its inner side against the side of hub 26 -and has-.a small hole 33 as a direct passage from channel 32 to the inside of gasket 30.

Hub 26. is furnished with one or more right-angled passages 34,- one branch. of which opens in the wall of hub 26 in .re isir with the annular channel 32 and the ot er 0 which leads downwardly I continuing through opening 35 in lockin plate 27 to directly connect the gasket wit the interior 3 of the tank. Holes 36 for the cap screws 37 are in staggered relation as shown in Fig. 3, so that plate 27 can only befasfened to hub 26 in. one angular position.

Inasmuch as the thickness of the'rubber in the two sides of gasket 'plus'the depth of brass ring 31 is purposely made greater than the depth of the gasket'chamber when I I locking plate 27 is in place, there is effected a premure-tight clam ing of the sides of gasket 30 from the en s thereof to the outer edges of the ring 31. Referring to Fi 2 it can be seen thatt'he upper side of gas et 30 is; clamped between the under side of phlilg t e asket is clam ed between the ring prevents any u1d. seepage or leakage i irind the ends of gasket 30 as to build up "'r'essures on the outside thereof along the walls of the chamber would probabl destroy the seal. Circular grooves 38 are thetop and bottom of brass ring 31 to aid the clamping of gasket 30. r

To begin the initial operation of a'tank using this invention, ri 31 is slipped inside sket 30 and then s 'pgedover hub 26 on P ug 20. Locking plate is then ut on in the onl position in which it can fastened tot e hub, and capsscrews 37 tight- Y ened. The gasket then 100 like a small tire embedded in lug 20. Once this assembly is so made, the gas et lasts indefinitely.- Plug 20 is .then conveniently screwed down by hand and left until the wanted effects take place in tank 10.

In making the gasket chamber which so closely confines gasket 30 to such accurate 'tained along the top and the ottom of the tortion and age 29 on loc in plate 27. This clamprnished of the end of the gasket as plu 20 is being screwed down. Also confining t e gasket 30 by means of a chamber which exactly measures the outside dimensions of the gasket with the exception of the clam ing effect obring'31, rmits every ounce of fl'uid pressure withm ,the gasket to make a seal. This would not be the case if the chamber were larger or smaller than'gasket 30.

In the embodiment described, the only .dis-

rmitted gasket 30 is intogroove 41 so that it wedges into any opening between plug 20 and tank 10, indicated in Fig. 5. As the diameter of locking plate 27 is substantiall the same as opening 40, there is the sma lest possible outside area of gasket 30 exposed to the direct action of the pressure within the tank. This unbalanceof pressures running from a maximum along the upper side of the gasket to a minimum in seat 18 where thetendency" to leakage or seepage past the gasket is most likely to occur.

By reversing the vertical branch of assage 3 1, tank 10 can be used as a vacuum ottle and during the exhausti thereof the atmos here will act on the inside of gasket 30 to e ectively preserve the vacuum within the tank This is' a mere reversal of one form of the invention and is considered to be a pgrt of the same. In fact, many changes may made in the form of this invention by one skilled in the art without departing from the scope thereof as defined by the following claims.

I claim:

.1. In a pressure tank, a mouth therefor, a machined shoulder around the inside of said mouth,.a small bevel at the end of said shoulder, a filleted surface leading from said bevel, a screw plug to close said mouth, a shoulder, a bevel and a filleted surface on the underside of said plug to register with the corresponding parts in said mouth, said filleted surfaces completin a semicircle except for a recess produced by the two bevels, a central hub on the underside of said plug, a U-shaped rubber gasket of uniform thickness surrounding saidhub, a ring of rectangular cross-section inserted between the sides of said gasket and closely fitting around said hub, a locking plate fitting in the open- 132 ing in the mouth of the tank and forming a flange running from the edge of the lower filleted surface to the hub, said flange forming a chamber with the underside of the plug 5 and the filleted surfaces which is filled exactly b the gasket, said plate clamping the sides 0 the gasket in immovable pressure tight position, an opening in said plate communicating with an openmg in said plug, an annular recess on the inner side of the ring registering with the aforementioned opening, a radial hole through said ring, and a discharge opening through said plate and said plug.

2. In a tank, a body member for holding a fluid under pressure, a closure member there- I for, and an inflatable gasket bearing against parts of the closure member and body member on opposite sides of a portion of the joint between the body member and the closure member and thereby forming a seal for the joint, one of said members having a passage extending therethrough for connecting the interiors of the gasket and body member.

3. In a tank for holding a fluid under pressure, a closure therefor, the closure and tank being formed to provide a gasket chamber, an inflatable gasket of uniform thickness within said chamber for sealing the joint between the tank and closure, and means for maintaining a pressure differential with respect to the sides of the gasket whereby the gasket is'so distorted as to provide a greater thickness ofmaterial in areas of greater sealdestroying pressures.

4. In a tank for holding a fluid under pressure, a closure therefor, said tank and closure being formed to provide a gasket confining chamber, an inflatable gasket in said chamber,

40 said gasket bearing against parts of the closure and tank on opposite sides of a portion of the joint'between the tank and the closure and thereby formin a seal for the joint, said portion of the joint eing located between the planes of the sides of the gasket, and means for maintaining a pressure differential with respect to the sides of the gasket whereby greater sealing effect is obtained in areas of greater seal-destroying pressures.

5. In a tank for holding fluid under pressure, a closure therefor, and a substantially closed inflatable gasket carried by said closure, said gasket being positioned to bear against parts of the closure and tank on opposite sides 01" a portion of the oint between the tank and closure and thereby form a seal for the joint, the closure having a passage extending therethrough for connectlng the interior of the garet and tank.

6. In a closure member, a U-shaped distortable gasket, a ring interposedbetween the sides of said gasket, a locking plate to fasten said ring and plate to said closure member and adapted to cause the sides or the gasket to be clamped against the ring in a pressure aeoaaeo by form a seal for the joint, and a conduit connecting the interior of the gasket and tank, at least one of the edges of the joint-forming portions of the closure and tank adjacent which the gasket bears being cut away to form a groove, the inflation of the gasket causing the same to be directed into said groove.

9. In a tank for holding a fluid under pressure, a closure therefor, said closure havm a gasket chamber, and an inflatable gas et within said chamber, said gasket, when inflated, bearing against and sealing a portion of the joint between the tank and closure, the closure having a passage extending therethrough for connecting the interior of the gasket and tank, at least one of the edges of the joint-forming portions of the closure and tank against which the gasket bears being cut away to form a groove, the inflation of the gasket causing the same to be directed into said groove.

In testimony whereor, I have signed my name to this specification.

HARRY H. PURVIS. 

